An adapter for use with an electromechanical surgical instrument. The adapter includes an elongate shaft assembly that has a distal end that is configured to be coupled to a surgical end effector and a proximal end that is coupled to an adapter housing assembly that is configured to be operably coupled to the electromechanical surgical instrument. The adapter includes seal arrangements for preventing fluid and debris entering through a distal end of the shaft assembly from reaching an electrical assembly supported in the adapter housing assembly.